Through the Registry for Research on Hormonal Transplacental Carcinogenesis, the investigators plan to expand their studies of the epidemiology, etiology, pathogenesis, biologic characteristics, management and prognosis of human genital cancers that develop after intrauterine exposure to exogenous sex hormones. A data bank which has been developed with details of each case will be utilized for the conduct of this research. Active canvassing of medical institutions will continue to obtain all cases of clear cell adenocarcinoma of the genital tract occurring in females born after 1940, with or without a history of maternal hormones, and all cases of genital cancer including squamous cell carcinomas of the vagina and cervix that develop in the exposed population. Studies on the age-incidence of diethylstilbestrol-(DES)-related clear cell adenocarcinomas will be extended, with particular emphasis on cases beyond age 24. Etiologic factors other than DES exposure will be investigated by a case-control study of affected exposed females ad their sisters. The possible role of exogenous steroidal hormones will also be studied. We shall evaluate squamous cell carcinomas of the vagina and cervix which others have predicted will occur in large numbers in the exposed population and also attempt to identify cancers that may develop at other sites in the female genital tract as a consequence of exogenous maternal sex hormones. Detailed clinicopathologic correlative studies will be directed toward a wide variety of host and cancer characteristics that may relate to the biology of the tumor. Attempts will continue to identify a precancerous lesion of clear cell adenocarcinoma and to expand the existing incomplete knowledge of treatment and prognosis. We shall remain a source of scientific information and consultation for this problem, and provide mechanisms by which qualified investigators may gain access to biologic materials from patients with these diseases.